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Mediterranean Basin forest ecosystems are recurrently affected by wildfires. The occurrence of insect pests following fire may be a critical factor affecting tree survival and forest recovery. Although ambrosia beetles are viewed with increasing concern, information about the host selection and colonization behavior of these beetles in Mediterranean broadleaf forests is very scarce and inexistent in areas affected by wildfires. After a forest fire in Portugal, we selected 841 burned and unburned cork oak trees and assessed the presence and intensity of ambrosia beetle attacks, as well as other tree characteristics, and used generalized linear models to investigate the factors driving host selection. In contrast with burned oaks, where beetle attacks were frequent, the unburned trees were little affected. Attacks in the burned forest were more frequent in larger trees that suffered higher fire severity, in trees being exploited for cork (but with thicker bark), and in trees that were closer to the unburned area. A contagious effect to neighboring unburned trees was not observed, and cork harvesting in subsequent years following fire also did not increase the probability of beetle attacks. These results help us to understand the risk of ambrosia beetle attacks and improve forest management in cork oak forests. [ABSTRACT FROM AUTHOR]

Eucalypts are among the most widely planted forest trees in the world, and outside their native Australian range, the main arthropod pests are sap‐sucking insects, defoliators, gall‐making insects and xylophagous beetles. We report on a new association between a polyphagous wood‐boring beetle and Tasmanian blue gum (Eucalyptus globulus Labill.) in Central Portugal. Unidentified wood‐boring insects were found attacking two three‐year‐old E. globulus trees showing signs of decline among otherwise healthy trees in a commercial plantation, in June 2018. Declining trees presented dead twigs and branches, and recently developed epicormic sprouts evident on the trunks. Insects emerging from logs were identified as Ambrosiodmus rubricollis (Eichhoff), a species native to eastern and southern Asia, with the taxonomic identification validated by molecular analysis. To our knowledge, this is the first record of A. rubricollis associated with a eucalypt species worldwide. It is not clear whether the beetles played any significant role on the decline of the trees, but Ambrosiodmus may be potential pests for several tree and shrub species in Europe, as these beetles can transport pathogenic fungi. [ABSTRACT FROM AUTHOR]